Series Land Rovers are well known for having poor fuel economy. You can drive a few miles into town and back and still not have the temperature reading normal on a cold day. So you get maybe 10mpg (16km/g, 2.2mi/l, 3.5km/l) - UK units. All this time the engine oil has been thicker than at normal operating temperature and so not doing such an effective job of lubrication - causing additional engine wear.
One common and cost effective approach to this problem is to fit a radiator blind so that the engine reaches normal operating temperature faster. But this can be a problem if your journey is not a short one, as the engine may overheat.
Fitting an engine pre-heater into the cooling system allows the engine to warm up before it is started. So fuel economy is immediately improved and lubrication is more effective from the start - even during the actual engine start-up, which is a critical time for wear to take place. The pre-heater will not lead to the engine reaching full operating temperature, but it should be possible to observe some movement on the temperature gauge before start-up. As bonus, you also get warm water passing through the interior heater before your journey begins.
A variety of pre-heaters are available, though German manufacturers seem to have a speciality in this area.
Before purchasing, consideration should first be given as to where the device could be mounted. So look at designs and specifications of pre-heaters first before opting for a particular model. Fortunately, Series Land Rovers tend to have more available space under the bonnet than many more recent vehicles. Bare in mind that it is a common requirement for the pre-heater to be mounted such that it has a significant head of coolant above it. In this particular case the manufacturer specified at least 20cm below the maximum coolant height.
Each photo below can be enlarged and seen in greater detail by clicking on it.
The model chosen here could not be mounted conveniently using it's in-built mounting points. So a bracket for it was fabricated from some scrap metal and the bracket mounted on the inner front LHS wing (photo 1). Instructions should be supplied with whatever pre-heater is obtained, but the main points are that it needs to be secure and away from the exhaust, brake and fuel lines and any moving parts.
It is also essential to mount the pre-heater such that tubing leading to and from it does not have any sharp bends that may restrict coolant flow.
The pre-heater is basically installed in that part of the cooling circuit that allows for coolant flow around the cylinder head prior to the thermostat opening. In the standard 2,286cc Series Land Rover engine shown here, the copper coolant pipe across the top of the cylinder head that carried coolant to the heater has been removed. It has been replaced by a longer rubber coolant pipe passing close to the inner wing and the pre-heater was incorporated into this.
The tubing needs to be secured so that no long lengths can move about, as they will be likely to when softened by hot coolant
. In this case a radiator cowl was present so the tubing was secured to that, ensuring that it was well clear of the fan blades. Also be prepared for the exisiting tubing from the thermostat housing to be of a different inner diameter that that required for the pre-heater. This was the case here and two reduction connectors were required (photo 2).
Free movement of all engine components must be ensured and the carburettor linkage was an issue in this particular case. The problem was overcome by securing the tubing to the standard exhaust heat shield that was already present. This also protected the rubber tubing from the exhaust manifold heat (photo 3).
Having checked the operation of the cooling system for leaks, the next job was to set up the mains charging system.
Again, care should be taken to mount the electrical wiring away from heat sources and moving parts and, remembering that it's on a Series Land Rover, bare in mind possible vulnerability to offroad damage.
In this case, it was opted to have the mains lead plug accessible through the front radiator grill for convenience. So a simple bracket was fabricated from scrap metal and secured as shown in photo 4.
It did become necessary to remove a few sections of the grill however to allow full and easy access for the mains lead adaptor (photo 5).
So now all that is necessary to pre-heat the engine is to plug in the mains adaptor and leave it on for about 30min (pre-heaters come in different power ratings, so timings vary). This pre-heater is rated 1500W so requires 6amp mains current.
Photo 6 shows the completed arrangement of the inlet and outlet coolant tubes and the electrical connection wire.
This article should not be taken as stand alone instructions for fitting an engine pre-heater. Full instructions as per individual device supplied by the manufacturer should be followed closely.
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